Flexible and stretchable multi-wavelength Micro-LED array device based on liquid metal electrodes

In this study, a flexible and stretchable multi-wavelength Micro-LED array device with a maximum strain of up to 254% was fabricated on an Ecoflex 00-30 substrate, using liquid metal as three-dimensional(3D) interconnect electrodes. First, simulations were conducted to analyze the influence of microchannel structures on the relative resistance change of the liquid-metal electrodes during device deformation. Subsequently, complex-shaped dual-layer microchannels were fabricated in a single molding step using a paraffin-wax microchannel sacrificial structure. Furthermore, a stable electrical interconnection between LEDs and liquid metal electrodes was achieved throughout the deformation processes by optimizing the shape of the LED pin electrodes. Finally, the fabricated device exhibited excellent optoelectronic stability under various deformation states. During the 0-100% strain process, the optical power and current changes of the Micro-LED were less than 2.5% and 2.9%, respectively. When the bending radius was reduced from infinity to 16 mm, both changes remained below 0.5%. This study holds significant potential for application and guidance value for fields such as phototherapy and flexible sensors.